Apparatus and method for ultrasound treatment for ballast water management

ABSTRACT

The invention provides a method of treating a target area with an ultrasound wave pattern, including: providing an ultrasound apparatus having an ultrasound wave generator operatively attached to a plurality of transducers, coupled to an immersible support and configured to emit an ultrasound wave; immersing the apparatus into a water environment; positioning the apparatus proximate to a target area to treat at least one in situ organism; and emitting a pattern of ultrasound waves from the transducers, the pattern of ultrasound waves additive in effect and emitted onto the target area to threat an in situ underwater organism.

PRIORITY CLAIM

This application claims priority to U.S. Provisional Application No.61/428,479, filed Dec. 30, 2011, and is a continuation-in-part of U.S.patent application Ser. No. 12/880,842, filed Sep. 13, 2010, which is acontinuation of U.S. patent application Ser. No. 12/103,421, filed onApr. 15, 2008, now U.S. Pat. No. 7,799,233, which claims the benefit ofU.S. Patent Application No. 60/912,254 filed on Apr. 17, 2007, each ofwhich are incorporated herein by reference in their entireties.

FUNDING STATEMENT

The invention was made with government support under the NationalOceanic and Atmospheric Administration (NOAA), contract numberNA16RG206, awarded by a cooperative program of the University of Vermontand Plattsburgh State University of New York, and with governmentsupport from the Department of Interior, grant agreement number30181AG098. The government has certain rights in the invention.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to an apparatus and method fortreating aquatic organisms with ultrasound waves. Specifically, theinvention relates to an apparatus for in situ control of underwaterorganisms and the method of use thereof, particularly for ballast watertreatment.

BACKGROUND OF THE INVENTION

Invasive species in non-native ecological systems and environments oftenresults in overpopulation of that species such that the native speciesand ambient environment is thrown out of balance. The invasive speciesmay out-compete native species for food and shelter, and may not haveany natural predators to keep non-native populations in check. Once aninvasive species is introduced into a non-native environment, thenon-native species may quickly repopulate the area, drastically shiftingthe ecological balance and system. For these reasons, vast resources areinvested each year in efforts to eliminate invasive plant and animalspecies in the United States and abroad. Previous control methods varywhether the species is microbial, animal, or plant.

The control and elimination of invasive aquatic animal species is doneby methods including, for example, physically catching and removing theanimals, sterilization, building mechanical barriers, or treating thewater chemical dispersions, toxic bait, or various pesticides. Thecontrol of invasive aquatic plants is done, for example, by mechanicalharvesting, manual removal, and chemical spraying. Each of theaforementioned methods of control and removal of invasive species haslimitations in use and problems and associated with it. Some of theproblems include the propagation and increase of pollutants,environmental and ecological damage, great cost, low efficiency, andoverall ineffectiveness.

Shipping carries more than 80% of the world trade and in the process 12billion tons of ballast water per year. Ballast water is an essentialpart of ship operations, providing trim, stability, propeller immersion,and maintaining safe levels of hull stresses in various states ofloading and unloading. However, invasive species are carried in vesselballast water and introduced via discharge of ballast water. Theglobalization of trade, the rising tourism and the massive volume ofcargo shipments have increased the chance of accidental introduction ofinvasive species. More than 10,000 species each day were estimated to betransported across the oceans globally in the ballast water of cargoships. Many species are able to withstand the hardships of a journeyacross the seas. When the ship docks, unloads its cargo and empties itsballast tanks, the plants, animals, microbes are then unintentionallyreleased into the new waters. Many of those species might successfullyadapt into the new environments, outcompete native species and causeeconomic, social, recreational and ecological losses.

Shipping is widely considered one of the most important causes ofanthropogenic changes to species distributions in the aquaticecosystems, including oceans, rivers, lakes and the like. It isdifficult to quantify the economic, ecological, recreational, and sociallosses caused by invasive species introduction via discharge of ballastwater. Even further, the cost associated with losses such as the loss ofnative species and ecosystem functions are simply impossible toestimate. It is crucial to improve current ballast water managementtechnology in order to reduce the economic, ecological, recreational andsocial losses caused by non-indigenous species introduction viadischarge of ballast water.

SUMMARY OF THE INVENTION

In one embodiment of the present invention, there is provided anapparatus for treatment of ballast water, including a generallycylindrical module having an open interior along its axis; a pluralityof transducer probes disposed in the wall of the module, each of theprobes having a first end and a second end, the second end being withinthe open interior of the module; a power source supply for at least oneof the transducer probes at the first end; where the transducer probesare capable of emitting ultrasonic waves at the second end. Anotherembodiment includes a system including a plurality of these modules.

In another embodiment, there is provided a method for treatment ofballast water, including the steps of providing a ballast water sourceincluding at least one organism to be destroyed; providing an apparatusincluding: a generally cylindrical module having an open interior alongits axis; a plurality of transducer probes disposed in the wall of themodule, each of the probes having a first end and a second end, thesecond end being within the open interior of the module; a power sourcesupply for at least one of the transducer probes at the first end; wherethe transducer probes are capable of emitting ultrasonic waves at thesecond end; powering on at least one of the transducer probes, therebyemitting ultrasonic waves within the interior; and flowing the ballastwater through the interior, whereby the ballast water is in contact withthe ultrasonic waves.

The present invention will be described in association with referencesto drawings of embodiments and description. It will be apparent to thoseskilled in the art that various modifications may be made withoutdeparting from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of the electrical components of an embodiment ofa single transducer of the present invention.

FIG. 2 is a diagram of the top view of an embodiment of the apparatus,being towed by a tow line.

FIG. 3 is diagram of the ultrasound emitted from the source plane of the(as in FIG. 2) to a target plane (in situ target area).

FIG. 4A is a computer model of an ultrasound wave pattern emitted by theapparatus at an exemplary distance from the target plane.

FIG. 4B is a computer model of an ultrasound wave pattern emitted by theapparatus at another exemplary distance from the target plane.

FIG. 4C is a computer model of an ultrasound wave pattern emitted by theapparatus at still another exemplary distance from the target plane.

FIG. 5 is a diagram of the apparatus in operation, being towed throughthe water by a vehicle.

FIG. 6 is a front view of an embodiment of the present invention withtransport members on an encasing member, which houses the electricalcomponents of the apparatus.

FIG. 7 is a cut away side view of a diagram of the apparatus, showingthe electrical components housed in the encasing member with loopconnectors associated to the encasing member.

FIG. 8A is an embodiment of a buoy as a transport member, attachable tothe apparatus for mobility.

FIG. 8B depicts an anchor attachable to the apparatus of the presentinvention to promote operation at a location.

FIG. 8C depicts another type of anchor attachable to the apparatus ofthe present invention to promote stationary operation at a location.

FIG. 9 is a diagram of the apparatus of the present invention inoperation, where the apparatus is in electrical communication with acomputer and power supply housed on a vehicle.

FIG. 10 is an illustration of the apparatus with an onboard transceiverin communication with a remote processor.

FIG. 11 is an illustration of two embodiments of the apparatus of thepresent invention in operation, one with a track transport member andthe other with posable propellers.

FIG. 12 is an embodiment of the apparatus of the present inventionincluding posable propeller transport members in operation to permeatein situ targets located a least partially beneath the sediment of awater floor.

FIG. 13 is a diagram of a plurality of apparatuses, each with atransceiver, in communication with a processor having a transceiver.

FIG. 14 is a diagram of the method of the present invention.

FIG. 15 is an embodiment of a ballast treatment system including aplurality of transducer probes per module.

FIG. 16 depicts a stepped probe used as an ultrasound transducer.

FIG. 17 is a photograph of one module of a ballast treatment systemincluding ten probes arranged in a spiral configuration.

FIG. 18 is an internal view of the module of FIG. 17 as viewed along itsaxis, showing the open center of the module through which water travelsduring use.

FIG. 19 is a normalized sound intensity representation along one probelocated on the left side.

FIG. 20 shows one embodiment of a control box which is used to controlall power supplies in the apparatus.

DETAILED DESCRIPTION OF THE INVENTION

The potential not only for continued existence of invasive populationsbut also expanding populations demonstrates an urgent need for a moreeffective approach in treatment and elimination while, at the same time,promoting ecological preservation and environmental make up. The currenttechnology and methodology is problematic and ineffective in managingtarget species and populations. Hence, a need exists to solve theproblem of treating, controlling, and eliminating invasive plant andanimal species with benefits associated with cost, efficiency,effectiveness, and ecological effects. Such is provided with theapparatus and method of use of present invention.

The present invention provides an apparatus, system, and method of usefor the treatment of in situ aquatic organisms with ultrasound waves inorder to facilitate elimination thereof. The target area may include oneor more organisms, including but not limited to invasive species. Anymaterial desired to be treated may be used in the present invention.Invasive species, as used herein, may refer to native species,non-native species which are introduced species into an environment orhabitat, or noxious species which create a nuisance. Invasive speciesnot only grow on their native range but can also expand their range tooutside of their historical boundaries. Invasive species are capable toadapt into wide ranges of environmental conditions and have a highreproduction rate. The device includes at least one power source,function generator, power amplifier, and ultrasound transducer.Optionally, the device may include an immersible support, a remotecontrol, computer system, and/or a transport member in order tofacilitate ease of use and operability.

In one embodiment, the apparatus may be useful as a submersibleapparatus. In this embodiment, the underwater aquatic apparatus may beimmersed or otherwise submerged in a control volume of water in order totreat one or more target species or desired area. Optionally, theapparatus may be remotely controlled, for example, from a nearby boat oreven an off-site facility. The apparatus may be maneuvered through thevolume of water by transport members, tracks, wheels, jets, and the likein order to place the apparatus an effective distance from the targetsite. The apparatus may be used in order to treat or eradicate one ormore target species or populations. The species may be non-native,invasive, or otherwise detrimental to the in situ site of their locale.

As the apparatus is maneuverable, robust, compact, and optionallyremotely operated, the device may be used to treat a geographic locationand reduce the population until a desired population is achieved.Similarly, once the objectives of one area may be realized, the devicemay be transported to a new location at which different parameters maybe employed in order to target a different target species or area. Assuch, the efficiency, effectiveness, and costs of treating oreliminating target species or populations are driven down. Further, theapparatus and method avoid causing damage or pollution to theenvironment or in situ ecological system. Once the target organism istreated, the matter is left to decompose in the ambient environment,thus returning the nutrients of the organism into the water and the soilwhile maintaining the integrity of the water bed floor, shoreline, andother wildlife, plant life and organisms.

In other embodiments, the apparatus may be employed in non-submersibleuses, for example, swimming pools, ballast water of ships, boats, andthe like, and the treatment of large control volumes of water or otherliquids or solutions including those containing cosmetics,pharmaceuticals, nutraceuticals, food or beverage. In one particularlyuseful embodiment, the apparatus and system described herein may be usedto treat ballast water in ships, boats, and the like. In thisembodiment, the device may not be a submersible device, but rather beuseful for flowing water, such as water flowing through a hollow pipe orseries of pipes.

The apparatus of the present invention may include a plurality ofultrasound transducers, which cooperate to emit a pattern of ultrasoundwaves aimed at a target area containing a number of target organisms.The pattern is created by a cooperative or additive effect of theultrasound beams emitted from each of the transducers. Though theultrasonic pattern emitted from the aquatic apparatus may have a drastictreatment effect upon the target population in the target area, as theultrasonic waves propagate the water, its intensity attenuates, andthus, the distance out of the focal length of the waves may be much lessaffected by the ultrasound. Therefore, the ultrasonic waves emitted fromthe aquatic apparatus of the present invention have limited range andlimited environmental impact while maximizing maneuverability, robustdesign, and effectiveness of treatment delivery.

Also, the ultrasonic pattern emission exerts limited environmentalimpact on the surrounding area compared to other means of control.Ultrasound equipment with no moving parts typically has a long lifeexpectancy of approximately over 30 years, thus the robust equipment iseasy to upkeep and may be used for decades. Further, the variousembodiments of the apparatus may be used to treat up to and over an acreof area per day. For example, the underwater aquatic device does notrequire that foreign substances, including chemicals, toxic bait, orpesticides be added to the water, the apparatus may be operatedyear-round, even with partially frozen cover over a control volume(treatment can start prior to a large development of biomass), retrievaland collection of the treated target or biomass is unnecessary; andequipment is robust with a long life expectancy.

Ultrasound is a sound wave whose frequency is above the audiblefrequency range for humans; i.e., frequency over 20,000 Hz. The relevantphysical principles of ultrasound include resonance phenomena andacoustic intensity. A mechanical system such as a gas bubble may havepreferred resonance frequencies. Preferred resonance frequencies aredetermined by the bubble's dimensions and also by the physicalproperties of the gas trapped in the bubble. When the frequency of anultrasound matches one of the resonance frequencies, the oscillationamplitude reaches a maximum value. Therefore, the oscillation amplitudemay become great enough to cause the bubble to rupture.

An ultrasound wave, as it passes through a water medium, may causebubble activities known as acoustic cavitation. Cavitation causes a widevariety of changes in living cells, ranging from microstreaming of acell's internal structure, to a mass disruption of cell walls. Acousticcavitation, one of the dominant mechanisms disclosed herein, isespecially evident on aquatic plants due to the presence of gas in theinterconnected chambers inside plant petioles, stems, and leaves. Asaquatic animals and plants have gas bubbles/pockets within their organsand structures, respectively, they become subject to acoustic cavitationwhen they may be targeted by an ultrasound wave. The present inventionincludes an apparatus, a system, and a method for ultrasound treatmentin order to control and/or eliminate aquatic plants and animals.

With reference to the Figures, a first aspect of the present inventionincludes an apparatus 100 for in situ control of underwater organisms.Referring to FIG. 1, the apparatus 100 may include a function generator10, for generating an electronic signal; a power amplifier 20,electrically coupled to the function generator 10, for receiving theelectronic signal and amplifying the signal; a plurality of transducers31, electrically coupled to the power amplifier 20, for converting theamplified electronic signal to a plurality of ultrasonic waves; and animmersible support 50, wherein the plurality of transducers 31 areoperatively coupled to the immersible support 50, wherein eachtransducer 30 generates at least one of the ultrasound waves to providea pattern of ultrasound waves 45 larger than an individual ultrasoundwave to thereby cover a larger in situ target area 70 than an individualultrasound wave.

Optionally, the function generator 10 and power amplifier 20 may behoused and contained within the immersible support 50 (shown in FIGS. 9and 10).

Optionally, the apparatus 100 may include a power source 110, as shownin FIG. 1. The power source 110 may be may provide the requisite powerto the function generator 10, the power amplifier 20, and othercomponents.

The function generator 10 may be any signal generator and may include,for example, a device for generating the electronic signal of any waveform. The power amplifier 20 may be electrically coupled 22 to thefunction generator 10 (FIG. 10), and may receive the electronic signaland amplify the signal to an amplified electronic signal. Optionally,the function generator and power amplifier may be combined into anelectronic device unit for use in the apparatus. The power amplifier 20may be any device that amplifies a small amount of electronic energy(e.g. power) to a larger amount of energy (e.g. power). The plurality oftransducers 31 may be electrically coupled 32 to the power amplifier 20(FIG. 10) for converting the amplified electronic signal 21 to aplurality of ultrasonic waves 40. The plurality of transducers 31 may beoperatively coupled to the immersible support 50. The transducers 31 maybe any type of electroacoustic device, for example, non-focusingpiezoelectric elements 35 (as shown in FIG. 10), focusing piezoelectricelements, ultrasonic horns, ultrasonic arrays of any forms, orultrasonic speakers.

The transducers 31 may be operatively coupled to the immersible support50, for example, by a removably attached connection 51 (FIG. 2). Each ofthe transducers 31 may be snapped into place, mounted onto, hooked intoplace, or even fitted into place on one or more portions of theimmersible support 50. Further, the plurality of transducers 31 may beadjusted or modified so that the relative size and shape of theimmersible support 50 and relevant transducer orientation may beappropriate for varying environmental conditions and confines. Asanother example, the transducers 31 may be fixed into place within theimmersible support 50.

The immersible support 50 may vary in size and shape and plurality oftransducers 31 in the array so as to be ideal and practical for variousapplications. By varying the array, so too may one vary the focallength, intensity, and/or additive ultrasonic pattern emitted by thetransducers. That is, the transducers 31 may be operatively coupled in avariety of ways to the immersible support 50, wherein each transducer 30of the plurality of transducers 31 may generate at least one ultrasoundwave to provide a pattern of ultrasound waves 45 larger than the atleast one ultrasound wave. As such, the pattern of ultrasound waves 45may thereby cover a larger in situ target area 70 and may have anadditive affect upon the target, creating a greater intensity than theindividual ultrasound wave.

The transducers each emit an ultrasound wave. Each ultrasound wave has afrequency (measured in KHz), an acoustic intensity (measured in W/cm²)sound pressure (measured in MPa), and duration of emission/treatmenttime (measured in seconds). Also, depending on the size of thetransducer, the beam dimension may vary (larger beam dimension withlarger transducer). For example, an ultrasound wave emitted by atransducer may have a frequency of 20 KHz, an acoustic pressureamplitude of 1.4 MPa, and a duration of 10 seconds.

The plurality of transducers together emit a plurality of ultrasoundwaves, which act in concert and have an additive effect as theypropagate through a medium to reach a target area or organism. Thepattern of ultrasound waves 45 may reach a sizable in situ target area70, have a greater intensity, and/or a greater focal region or multiplesmall focal regions as compared to an individual ultrasound wave.

Moving the transducers may in turn modify or adjust the pattern ofultrasound waves emitted there from. Pattern modification may beaccomplished, for example, by changing the orientation of eachtransducer 30 in respect to one another or by changing the orientationof the plurality of transducers 31 to a target plane or target area, asdefined below. By dynamically adjusting the electronic signals, anultrasound beam may be steered or patterned to different locations inthe array, for example, to a sub-target location due to extent ofinfestation.

As used herein, the target plane or target area may refer to an in situtarget area 70. This in situ target area may refer to the apparatus 100targeting one or more phenomena where the phenomena occurs, or withinits environment. As an example, various living organisms may be targetedby the present invention at their aquatic in situ location. For example,this target area may directed to the floor of a water body (penetratingat least a partial distance into the sediment of the floor to reachtargeted organisms), the water's surface (to reach, for example,submergent aquatic plants and/or algae), a cubic volume of water orliquid within an area, or even a superficial control volume of water (asan anti-fungal treatment for cosmetics, or as comestible purification),such as, for example, that of a swimming pool or a ballast tank in anboat or ocean vessel (to treat for microbes, bacteria, and/or insects).Alternatively, as will be disclosed herein, the in situ target area mayrefer to the living organism targeted by the apparatus, method, andsystem within its in situ location.

The in situ target area 70 may include at least one living organismselected from the groups including, for example, aquatic plants, alga,crustacean, mussel, fish, amphibians, animals, insects, plankton,bacteria, microbes, single-celled organism, and the like. Specifically,parameters of the apparatus may be directed to known limitations of thepetioles or stems of aquatic plants, air pockets or gases located in thegills and brains of animals, and gases in plankton, algae, andsingle-celled organisms in order to cause acoustic cavitation whichresults in cell and tissue damage, ultimately weakening the organism oreliminating the organism altogether. These examples are meant to benon-limiting, and may include various classes of aquatic plants,including free-floating plants, submergent plants, emergent plants, androoted-floating plants. It should be noted that any organism that may beconsidered or classified as threatening to the balance of an ecosystemmay be in situ target areas for the purposes of the present invention.It is important to note that once the in situ target area is treated,the target or organism is left in its in situ position and location.Thus, the treated organisms in a target area may serve as a source offood for desired organisms. Also, the decomposition of the treatedorganisms may enrich the soil of the ambient and provide nutrient richsediment. Each of these post-condition treatments will serve not only toremove the targeted organisms from the environment, but will also returnto the nutrients of the organism to the soil at the water's floor,providing desired non-targeted organisms with food, room to expand, andotherwise promote the in growth, development, and support of the desiredorganisms and species.

Incorporated herein by reference in their entirety are severalpublications which detail the ultrasonic treatment of aquatic plants,including: Wu, M. and J. Wu., 2007, Laboratory investigation on effectsof ultrasonic control of water chestnut, Journal of Aquatic PlantManagement 45:76-83; Wu, M. and J. Wu, 2007, Can ultrasound eradicatewater chestnuts? Journal of Ecological Restoration 25(1): 64-65; and Wu,J., and M. Wu, 2006, Feasibility study of effect of ultrasound on waterchestnuts, Journal of Ultrasound in Medicine and Biology 32(4):595-601.

The immersible support 50 may be a variety of configurations of varyingdimensions, and composed of materials, as may be desired. For example,the support may be in a circular configuration, an angled bar, ageometric shape, or along a straight line or bar (FIG. 2 (flat plate);FIG. 6 (generally circular bar); FIGS. 9 and 10 (geometric shapes. As anexample, the immersible support 50 may have a diameter of 40 cm with 20evenly spaced transducers located about 18 degrees from one another. Thediameter of the immersible support 50 may be large or small, or ofvarying sizes and shapes, as may be desired. The immersible support mayfurther include at least one attaching member 52 to attach the removablyattach wiring to the support.

Optionally, the immersible support 50 may have a hollow interior tofacilitate the wiring feed to communicate the plurality of transducers31 to the power amplifier 20 and function generator 10.

The apparatus may include a transport member 90, as shown in FIGS. 6, 9,10, 11, and 12. The immersible support 50 may provide attaching areas orcontact points for the connectors to attach to the transport member 90to the apparatus. The immersible support 50 may likewise have aplurality of perforations 60, vias, holes, bores, protrusions, loops (55a-c), or inconsistencies as shown in FIG. 2 and FIG. 7 to attach thesupport to a float, buoy 62, weights, anchor 61, or other type of deviceto facilitate transport or anchoring, as may be desired (shown, forexample, in FIGS. 8A-8C). That is, the immersible support 50 may beconfigured to reduce deforming drag that may act upon the support andtransducers as the apparatus may be used, in order to maintain theconfiguration of transducers and structural integrity of the apparatus100. Similarly, the perforations or loops may be used to attach theapparatus 100 to a tow line or tie 58 to attach to a boat 57 fortransport, as may be shown in FIG. 2 and FIG. 5. As a result, theemitted pattern of ultrasound waves 45 may be constant, calibrated, andmeasurable.

FIG. 3 is a depiction of the x, y, z axis of an embodiment of thepresent invention by using, for example, a central location of theapparatus 100 as the origin, labeled O. FIG. 3 is a diagram of theapparatus 100 in operation on the in situ target area 70. When theplurality of transducers 31 emits the pattern of ultrasound waves 45,the waves travel together and hit the in situ target area in varyingpatterns. The pattern depends, as previously disclosed, on the number,location, and configuration of transducers 31. For example, theorientation of the transducers from one another and the displacement ofthe plurality of the transducers 31 from the in situ target area 70 maycause different patterning effects.

Computer models of the various ultrasound patterns are depicted in FIG.4A through 4C. FIG. 4A, FIG. 4B, and FIG. 4C, as referenced herein,depict a set of computer simulation results of the normalized acousticpressure distributions at three different target planes. That is, thepattern of ultrasound waves 45 of a given orientation may differ for avarious distances of the in situ target area. These variations may becharacterized by the varying acoustic pressure patterns, as simulatedherein. The values of z in FIG. 4A, FIG. 4B, and FIG. 4C represent thedistance between the apparatus 100 and the in situ target area 70 plane.The various computer simulated ultrasound wave pattern 45 may bedistinct for different in situ target area 70 plane distances asmeasured from the origin of the apparatus 100. FIG. 4A represents adisplacement from the apparatus 100 to the in situ target area 70 (inthe z axis) of 0.5 meters. FIG. 4B represents a displacement from theapparatus 100 to the in situ target area 70 (in the z axis) of 1.0meter. FIG. 4C represents a displacement from the apparatus 100 to thein situ target area 70 (in the z axis) of 1.5 meter. As depicted inFIGS. 4A, 4B, and 4C, the computer simulations each depict acousticpressure patterns that are easily distinguished from one another, aseach differs from the next in the relative shape (or pattern) ofacoustic pressure. These varying acoustic pressure patterns may belikewise characteristic of a different ultrasound wave pattern 45 ofemission from the apparatus 100 at different displacements from the insitu target area 70 plane.

In FIG. 5, the in situ target area 70 plane may be parallel or otherwisegenerally along to the water surface, emitting ultrasound waves eithertowards or away from the surface. When used with a boat or othervehicle, the apparatus may be attached to the vehicle at one or morecontact points 60. The contact point 60 may be one or more of the formspreviously discussed, as utilized by the transport connector 58 toassociate the apparatus 100 with the transport member 57.

In use, the apparatus 100 may be configured to emit the pattern ofultrasound waves in any one of a number of desired angles ororientations towards the target area 70.

Optionally, as shown in FIG. 7, the apparatus may include an encasingmember 54. The encasing member 54 may be configured to encase thefunction generator 10, the power amplifier 20, the power supply 110,and/or at least a portion of the transducers 31. The encasing member 54may secure and protect the electronic components from damage uponimmersion.

In this orientation, the apparatus may be left for a period of time toemit ultrasound waves on an in situ target area 70 which may be moreconcentrated or more highly populated with one or more targetedorganisms. In such a configuration, it may be necessary for eitherbuoyancy or weight to be added to the apparatus 100 to facilitate theencasing member 54 to either have a tendency to float or sink.

FIG. 7 shows three potential locations of a connection loop 55, at 55 a,55 b, and 55 c. The connection loops 55 a, 55 b, and 55 c may swivel orotherwise freely rotate. The connections loop 55 may be used to attachthe apparatus to a buoy, anchor, or combination thereof. It may bedesirable to treat a location (thus anchor the apparatus) or to treat anarea by dropping off the apparatus upstream and retrieving it after ithas floated downstream (buoy). FIG. 8A through 8C depicts a buoy, anchorwith line, and anchor with rigid bar, respectively.

For example, the connection loop 55 may be oriented with the transducers31 towards the surface, water bed, shore lines, upstream or downstream,as may be desired.

Referring now to FIGS. 9-12, the apparatus 100 may optionally include atransport member 90. The transport member 90 may be operatively coupledto the immersible support 50 for mobility. The transport member 90 maybe selected from the group consisting of: a jet 91, a propeller 92, awheel, a track 94, a robotic arm, a fin, a paddle, and combinationsthereof. For example, the posable propellers may be moved in varyingdegrees in order to move the apparatus 100 to a location. The jet may bea result of, for example, a release of pressurized air or a forcedoutput of water. A wheeled (or tracked) system may be used in aquaticoperation, for example, in amphibians or very shallow applications. Thetracked and wheeled apparatuses may be used for fully submergedoperation on a water body floor or bed.

FIG. 10 illustrates the apparatus 100 of FIG. 9, as it may be suppliedwith power by a power supply 110. Alternatively, the power supply 110need not be supplied from a transport member 58 (as shown in FIG. 10),but may be, for example, an on-board battery, engine, or a solar energypack. Such a power supply 110 which may provide power to the apparatus100 so that it may be independently operable and mobile.

Optionally, the apparatus 100 may be a remote operated vehicle (ROV) asshown in FIG. 9. The apparatus 100 may further include an umbilical cord59. The cord 59 may house video feed lines, electrical cables, and thelike as may be desired. The central computer 130 and power source may belocated on a boat or other vehicle which may store the ROV between usesand tow the ROV during operation. Referring to FIG. 11, specific targetsincluding algae 72 and mussels 75 may be targeted by the two embodimentsof the apparatus 100 shown.

Optionally, the apparatus 100 may further include a transceiver 120(FIG. 10, 13). This transceiver 120 may be configured to communicatewith a remote processor 140. In FIG. 14, an apparatus 100 may be shownin wireless communication with a remote processor 140. The transceiver120 may send aquatic apparatus data to the remote processor 130. Suchaquatic apparatus data may include ultrasound wave pattern emissiondata, location data, observation data, etc. Alternatively, thetransceiver 120 may receive instructions from the remote processor 140.Such instructions may include changes in ultrasound wave patternvariables, change in position, etc.

The power supply 110 may include a solar cell or a fuel cell, either ofwhich may be located in a position adjacent to the immersible support50, but in communication with the aqueous environment.

The pattern of ultrasound waves 45 may be emitted through a volume ofwater, through water onto a hard submerged surface such as a boat or adock, towards the water's surface, or into the water body floor 5, wherean in situ target population may originate (e.g. germinate or hatch) andgrow prior to adulthood.

It is within the scope of the invention to utilize a plurality ofapparatus 100 in an area with a central computer in order to use asystem to manage and control in situ aquatic organisms (as shown in FIG.13). Each apparatus 100 may have a transceiver 120 capable ofcommunicating to a remote computer 140, where the apparatus isconfigured to receive operating instructions and parameters from thecomputer 140.

For example, the present invention may include an environmentaltreatment system which includes a plurality of mobile ultrasoundapparatuses 100, with a transceiver 120 coupled to one of each apparatus100. A remote processor 140 may be configured with a transceiver tocommunicate with, guide, transmit, and receive and interpret data fromthe transceiver 120 of each apparatus 100. The remote processor 140 maytrack population, population density, organisms treated, organismseliminated, GPS data of target location, size, and apparatus locations.Further, the remote processor 140 may send instructions to reposition,refine the ultrasound wave patterns, or change the duration of emissionof ultrasound from the transducers.

The remote processor 140 may include a remote processor to process andmanipulate data collected by each apparatus 100. The data may be theresult of an aquatic survey, a global positioning system image, a mapdetailing a latitude and longitude, et cetera. Further, the remoteprocessor may include a data of a projected population density of the atleast one living organism target population. The remote computertransceiver and the transceiver of each apparatus may communicateinformation, data, and instructions back and forth though wirelesssignals that may be received and transmitted by each of the respectivetransceivers.

Another aspect of the present invention provides a method 300 oftreating a target area with an ultrasound wave pattern, as depicted inFIG. 14. The method 300 includes: providing an ultrasound apparatus 310having an ultrasound wave generator operatively attached to a pluralityof transducers, each of the transducers configured to emit an ultrasoundwave, the plurality of transducers coupled to an immersible support;immersing the apparatus into a water environment 320; positioning theapparatus proximate to a target area to treat at least one in situorganism 330; and emitting a pattern of ultrasound waves from thetransducers, the pattern of ultrasound waves additive in effect andemitted onto the target area to threat an in situ underwater organismwith an ultrasound wave pattern 340. The ultrasound wave generator mayinclude, for example, a signal generator, a power amplifier, a functiongenerator, and a power source, electrically connected to one another aspreviously disclosed.

The step of immersing the apparatus may include maneuvering theultrasound apparatus 320 with a transport member to a position beneaththe water surface, the transport member attached to the immersiblesupport. The step of positioning the apparatus 330 may include movingthe apparatus to a predetermined distance from the target, where thepredetermined distance is within the range of the pattern of ultrasoundwaves emitted by the transducers. The step of emitting the pattern ofultrasound 340 waves may further include emitting an acoustic pressurefor a predetermined period of time onto a surface of at least oneorganism.

The method may further include the step of damaging the in situ targetsby acoustic cavitation. Also, the method may include the step oftransmitting information to a central processor for collection andprocessing. Further, the method may be repeated on an organism,population of organisms, on the target, or in an environment until adesired effect is reached. The desired effect may be elimination of acertain percentage of a population, eliminating a population, and thelike, until a desired level of treatment has been administered.

Next, the method 300 includes positioning the apparatus proximate to anin situ target area of aquatic organisms 340. The in situ target may beselected from the group of living organisms, as previously discussed.The method step of positioning the apparatus 340 may further includemaneuvering and aiming transducers of the apparatus with a transportmember to a predetermined distance from the target 341.

Finally, the method 300 includes emitting the pattern of ultrasoundwaves onto a surface of the plurality of in situ aquatic organismslocated in an in situ target area 340. Emitting a pattern of ultrasoundwaves includes emitting a frequency and an acoustic pressure for apredetermined duration. The apparatus may be moving through the waterwhile emitting the ultrasonic pattern of waves towards the in situtarget area. Also, by moving the ultrasound wave generator andpiezoelectric element through the water, the method of ultrasoundtreatment 300 may generating a larger treatment area than a stationaryapparatus 100 to thereby cover a larger in situ area than an individualultrasound wave 353. Through the at least one emission, the method 300may also include the step of damaging the in situ targets by acousticcavitation 370 (not shown).

The various positions and emissions may be recorded as the method mayinclude transmitting at least one method data to a central processor,and collecting the at least one data to the central processor 360.

It should be noted that the method 300 of ultrasound treatment may bereiterated or repeating 350 as many times as needed within a giventreatment. Therefore, the method 300 may further include the step ofreiterating 350 the steps of 330 positioning the apparatus and 340emitting the pattern of ultrasound waves onto a surface of the pluralityof in situ aquatic organisms.

In an alternate embodiment, which may be seen in FIGS. 15-20, theapparatus may be designed for the treatment and management of ballastwater, such as in cargo ships or other similar seafaring vessels. Thisembodiment includes the use of a generally cylindrical module, having ahollow interior along its axis, and a plurality of transducer probesarranged along the axis of the module. In the ballast water embodimentdescribed herein, the module is not submerged into water, but ratheruses water running through the hollow interior of the module, where itflows past a plurality of transducer probes. The use of ultrasonic wavesproduced by the transducer probes as explained above is useful intreating the water running through the center of the module.

As explained above, ballast water often contains living organisms, whichincludes water having at least one organism to be treated as definedabove. For ballast water treatment, it may be desired to have untreatedballast water first travel through a commercially available filtrationsystem having a filtration capacity of about 35-100 microns prior totreatment with the inventive ultrasonic system. As may be appreciated,initial filtration can be useful to remove larger-sized materials priorto treatment. The use of a separate filtration system is an optionalcomponent that may be omitted if desired. If used, one particularfiltration system that may be used is a Hyde Guardian® Filtrationsystem, which uses a disc filtration technology. This system uses thinpolypropylene discs that are diagonally grooved on both sides toapproximately 50 microns, which are then stacked and compressed along aspine.

When stacked, the groove on top runs opposite to the groove below,creating a filtration element with a statistically significant series ofvalleys and traps for solids. The stack is enclosed in a corrosion andpressure resistant housing. After the filtration system, solid materialswhose sizes are greater than about 35-100 microns will be separated fromthe water. Five 4″ filters with “internal backwash” are used. Thefiltration system has a unique self backwash capacity (outlet flow fromthe filters is stopped for a short time by closing a valve on thedischarge side. Pressure is boosted during backwash period by a separatebooster pump of the system. Five individual filter modules arebackwashed in sequence for 10 to 20 seconds each). The separated solidparticles will be washed out the system periodically. The filteringdiscs can be used repeatedly for a long time.

As noted, the optional filtration system as described above comprisesonly one possible filtration system that may be utilized before ballastwater enters into the ultrasonic treatment system. Any other filtrationsystem of similar capacity may be used with the inventive treatmentsystem if desired.

One representative schematic system useful in the treatment of waterballast is seen in FIGS. 15-16. As can be seen, the system 400 includesan initial source of water 410, which contains a number of materials,such as organisms, to be removed. These materials may include any knownspecies to be removed, including organisms such as bacteria, viruses,fungi, zooplankton, phytoplankton, egg and larvae stages of fish andinvertebrates, and other organisms to be removed. The water source 410may optionally travel through a commercially available filtration system420, which is useful to remove larger-sized organisms.

After traveling through the optional filtration system 420, the ballastwater then travels along the interior of a pipe 430 in which it istreated. The pipe 430 may be any desired material, including plastic,metal, or combinations thereof. Connected to the pipe is at least onemodule, which will be described in further detail below. The module is agenerally hollow tubular apparatus, which includes a series oftransducer probes 440A and 440B, past which the ballast water flows. Themodule and its probes 440 will be described in further detail below.

In one embodiment depicted in FIGS. 15-16, each module includes twoprobes (440A/440B), which are connected to a controller and poweramplifier 450. In FIG. 15, five modules are depicted (for a total of tenprobes 440), but it is to be understood that any number of modules maybe used, each module having any desired number of probes 440, as will bediscussed below. For example, there may be from one to about ten modulesused in series, with each module including from one to about twentyprobes 440. As the ballast water flows through the pipe 430 and throughthe interior of the module(s), the water is treated via the ultrasonicwaves emanating from the probes 440A/B. Each transducer probe 440operates at a frequency from about 20 kHz to about 3 MHz, with a desiredfrequency, such as about 20 kHz to about 50 kHz. The power used for eachprobe may be from about 750 W to about 15 kW.

Ultimately, the resulting water is treated in a ballast tank 460.Preferably, treated water in the ballast tank 460 has as few livingorganisms remaining after treatment as possible and desirably, the levelof remaining organisms after treatment is at or about zero organisms.

FIG. 16 shows a close-up schematic representation of one module thatincludes a pair of probes in FIG. 15. As can be seen, the probes 440A,440B are inserted into a pipe 430 at varying orientations. The pair ofprobes 440A/B in FIG. 15 represents one treatment module, the modulebeing a generally cylindrical pipe connected to the pipe 430. Atreatment module may include any number of probes 440, and is notlimited to only two probes 440, for example, each module may includefrom 2 to about 20 probes, or alternatively may include from 5 to 15probes, and in some embodiments may include about 10 probes. In someembodiments, the probes may be arranged in a linear fashion along themodule, or may be arranged so as to be opposed from each other acrossthe diameter of the module. In some other embodiments, described below,the probes 440 may be arranged in a helical spiral along the module. Aswill be described below, one factor to consider in the design of themodule is the spacing between adjacent probes 440. Too much spacingresults in void areas in which treatment is ineffective and too littlespacing results in an overcrowded design and less treatment efficiency.

FIGS. 17-18 depict one particular design for a module including ahelically arranged plurality of probes. FIG. 17 depicts the module 500as seen from its outside and FIG. 18 depicts the inside of the module500 as seen along its axis. As can be seen, the module 500 is agenerally hollow, tubular member into which a plurality of probes 510are disposed. Each probe 510 extends through the wall 520 of the module500, so that a first end 530 is outside the module 500 and a second end540 is inside the hollow interior of the module 500. As explained above,in the treatment of ballast water, the water to be treated runs throughthe hollow center of the module 500, and thus the module 500 isdesirably water tight. The probes may be held in place through anymechanical means, including use of washer, o-ring, and nuts to preventleakage of water from the pipe. It is particularly desirable that theprobe 510 be secured in a water-tight configuration, since water willflow through the interior of the module 500 and past the probe 510.

As depicted in FIG. 17, the plurality of probes 510 is arranged in agenerally helical formation, spiraling along the axis of the module 500.The helical design may warrant the relative uniformity of the ultrasoundintensity within the module 500, thus providing enhanced treatment.Other arrangements, such a linear, quasi-linear, or random arrangementsmay be used as desired. Any number of probes 510 may be used in themodule 500 as desired. For example, an individual probe 500 may includefrom 2 to about 20 probes 510, or may include from 5 to 15 probes 510,or may include about 10 probes 510. The number of probes 510 per module500 is a matter of choice, and may have a correlation to the size of themodule 500, the size of the probes 510, and the water flow rate throughthe module 500.

As depicted in FIG. 18, the second end 540 of each probe 510 extendsinto the interior region of the module 500, that is, the open center ofthe module 500. The second end 540 of each probe 510 is disposed to beat a relatively close distance to the wall 520 of the module 500. Aprobe 510 having a length of about 36 cm, the center-to-center distancebetween adjacent probes 510 (measured at the second end 540) may beabout 10 cm.

As can be seen in FIG. 17, the first end 530 of the probe 510 includesan electrical connector and wire, which is connected to a control panel550. In some embodiments, each probe 510 may be connected to anindividual power supply 550, or alternatively, a single power supply 550may be connected to each of the probes 510. Each power supply 550 isconnected to a control box, which may include one control box per powersupply or, alternatively, a single control box for a power supply 550for all probes 510. A single control box 560, as depicted in FIG. 20,may include control switches, such as a pump reset switch, a water pumpon/off switch, probe on/off switches, and the like. The control box andpower supplies 550 are connected to an electrical power source (notshown). Each module 500 may be operated at the same time or they may beoperated individually as water flows through the module.

As stated above, each module 500 may include any number of probes 510 asdesired. Each probe 510 may be spaced apart from an adjacent probe 510by any desired distance, which may be related to the overall size of themodule 500 and/or the size of the probes 510. For example, it may bedesired that adjacent probes 510 be spaced apart from each other by adistance of from about 10 to about 300 mm as measured by the center ofthe axis of adjacent probes 510. It is particularly desirable that theprobes 510 be inserted into the module 500 along a line that issubstantially along the diameter of the module 500. That is, theneighboring probes should be kept a certain distance, such as about 10cm, along the axial direction of the module 500. Desirably, each probe510 should cross the axis of the module 500, though each probe 510 maybe at a different angle relative to each other (See FIG. 18).

There are a number of physical properties that may be adjusted dependingupon the desired size of the module 500. For example, the length of themodule 500 along its axis and the diameter of the module 500 areproperties that may be considered. Other properties include the lengthand diameter of the probes 510, the distance between adjacent probes510, the shape of the probe 510, the layout of the probes 510 along themodule 500 (i.e., spiral, linear, etc.), the level of power provided tothe probes 510, the number of probes 510, and the like. Each of thesecharacteristics may be modified as necessary to achieve the desiredmodule 500.

In one embodiment, each transducer probe 510 may operate at about 20 kHzwith an electrical power supplied to it of about 750 W. Any electronicpower may be supplied, such as from about 500 W to about 20 kW, and moreparticularly from about 750 W to about 2 kW. The separation betweenadjacent transducer probes 510, as measured at the center of the axis ofeach probe 510 may vary depending upon the size of the apparatus used.It is particularly preferred that each transducer probe 510 besubstantially aligned along the diameter of the module 500 (i.e., theprobe 510 intersects the center of the module 500 along its axis), butsome variation is permitted.

The module 500 may have any desired length and diameter, and in someembodiments, the diameter of the module 500 may be from about 150 mm toabout 1000 mm. As will be described in further detail below, the lengthof the module 500 may be about 1.25 m. The first module 500 in thesystem is connected to a water pump, which determines the water flowrate through the system. The water flow rate is determined by the pumpflow rate capacity, and may be any rate from about 10 m³/hr to about5000 m³/hr. The flow rate of the water may determine the number ofprobes 510 to be used; that is, it may be desired to include more probes510 with a faster flow rate, and vice versa.

It is understood that the relative lengths of the modules and theprobes, as well as the number of probes used in the system may beincreased or decreased as desired. For large scale ballast tanks totreat fast flow rate of water, for example, the module and probe mayeach be about 2 to about 10 times the size discussed above to make surethat the organisms to be treated have sufficient contact time with theultrasound field. It is desired, however, that the relative lengths anddiameters of the module and the probes be maintained in a similar ratiowith respect to each other.

If desired, more than one module 500 may be used in a system, with eachmodule 500 being secured to an adjacent module in sequence. Securementmay be made through any desired means, including general pipe connectorsand the like. Securing more than one module allows for more probes 510to be included in the system. For example, one system may include twomodules, three modules, five modules, or more than five modules insequence. Any known connector may be used to join adjacent modules. Thenumber of probes associated with each module may vary as desired. Forexample, two modules, each having ten probes, may be used in sequence,thus providing a total of twenty probes in the system. In anotherembodiment, three modules, each having ten probes, may be used insequence, thus providing a total of thirty probes in the system.

A system includes at least one module. Zero, one, or more than onemodule in the system may have helically arranged probes, while zero,one, or more than one module in the system may have linear or randomlyarranged probes. For example, all modules in a system may have helicallyarranged probes, and all modules in a system may have linear arrangedprobes. Alternatively, at least one module in the system may havehelically arranged probes and at least one module in the system may havelinearly arranged probes. The selection of probe arrangement in eachmodule may be varied to achieve the desired result. Of course, asexplained above, the number of probes 510 per module 500 may vary asdesired.

In one embodiment, a module 500 may be employed, which is generallytubular in shape, having a hollow center and a plurality of steppedprobes aligned substantially spirally along the axis of the module 500.The module 500 may include from about 2 to about 20 probes, and moreparticularly from about 5 to about 15 probes, and most preferably about10 probes. Each probe is approximately the same size and shape as eachother, and has a diameter from about 10 to about 100 mm, and moreparticularly from about 20 to about 50 mm, and most preferably about 25mm in diameter. The probe length is about 200 to about 1000 mm, and moredesirably about 300 to about 500 mm, and most preferably about 360 mm.

Each probe in the module 500 is powered by a control panel or series ofcontrol panels. The power supplied to each probe is about 75 W to about20 kW, and more desirably about 500 W to about 1 kW, and most desirablyabout 750 W per probe. The distance between adjacent probes, as measuredfrom the center of each probe's axis is about 10 to about 300 mm, andmore desirably about 50 to about 200 mm, and most desirably about 100mm.

The module 500 length may be any distance, and in some embodiments maybe about 500 mm to about 2500 mm, more desirably about 1000 mm to about1500 mm, and most desirably about 1250 mm. The module 500 diameter maybe any desired diameter. The internal diameter (measured from theinterior surface of the wall 520) may be from about 150 mm to about 1000mm, more preferably from about 200 mm to about 500 mm, and mostdesirably about 240 mm. The wall 520 may be any thickness desired, andmay be from about 5 mm to about 50 mm, more preferably from about 10 mmto about 25 mm, and most desirably about 15 mm.

In one embodiment, a module 500 may be about 1250 mm in length, havingan internal diameter of about 240 mm, a wall 520 thickness of about 15mm, including about 10 probes 510, wherein each probe is generallycylindrical and is about 25 mm in diameter and about 250 mm in length.Each probe 510 may be disposed through the wall 520 of the module 500such that each probe 510 passes a length beyond the radius of the module500 but does not touch the opposite side of the wall 520 of the module500 (as seen in FIG. 18).

A method of using at least one module 500 in ballast water treatment isalso provided herein. In use, the ballast water is pumped through thecenter of at least one module, or series of modules, and the transducerprobes emit ultrasonic energy, as explained above. A treatment systemmay include one module or more than one module connected in series, suchthat the open interior of each module is connected to the open interiorof an adjacent module in a substantially water-tight fashion to allowthe flow of water through the series of modules. The treated water isthen fed to a ballast tank as clean water.

The system described herein for treatment of ballast water usesultrasound transducers (or transducer probes), operating at desiredfrequencies. It may be desired that each transducer probe operate at afrequency of about 20 kHz, which is low enough to generate acousticcavitation. Acoustic cavitation creates bubble activities, which cangenerate local high acoustic pressure, high shear stress, and hightemperature environments, as well as free radicals such as H+ and OH—.This, in turn, results in mortality of variety of organisms, asexplained above. Through using a plurality of transducer probes inindividual modules, the position and arrangement of the probes cangenerate relatively uniform sound field in order to eliminate theorganisms to be eliminated. Most desirably, the probes are arrangedsubstantially helically along the axial length of the module, but may bearranged in linear or quasi-linear arrangements, as well as randompatterns along the module.

The probes 510 may take any desired shape, and in preferred embodimentsthe probes 510 are a stepped-probe-design as seen in FIGS. 17-18. Theseprobes 510 may generate relatively uniform acoustic fields along thediameter direction of the module, as can be seen in FIG. 18. FIG. 19shows one representative stepped probe 510 useful in the invention, andits normalized sound intensity emitted. As can be seen in the FIG. 19,the sound intensity reaches its maximum at the tip of the probe 510,which corresponds to the second end 540 as explained above. Since thedepicted probe 510 is a stepped probe, at various points along the probe510, the sound intensity may vary. A non-stepped probe 510 may be usedif desired. During use, as water flows through the hollow interior ofeach module 500 used in the system, and past the probes 510 of eachmodule, the relatively uniform sound field within the module 500generated by the probes 510 generates a high pressure and temperatureenvironment, which results in mortality of a number of organisms, thustreating the ballast water. As discussed above, it is desired that thetreated water have at least an 80% mortality of the organisms to betreated, and more preferably at least 90% mortality of the organisms tobe treated, and most desirably at least 99% mortality of the organismsto be treated.

The foregoing description of the embodiments of this invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed, and obviously, many modifications and variations arepossible. Such modifications and variations that may be apparent to aperson skilled in the art are intended to be included within the scopeof this invention.

EXAMPLES & EXPERIMENTAL DATA Introduction to Experimental

A study was conducted to investigate the potential of the ultrasoniccontrol of water chestnut in efforts to effectively damage plant cellsand tissues to prevent population expansion and growth. The Waterchestnut (Trapa natans L.) is an annual aquatic macrophyte with floatingleaves around a central stem and feathery, adventitious submersedstructures which effectuate nutrient absorption and act as submergedanchors for the plant. Water chestnut leaf petioles are filled with gaschambers. The spongy inflated leaf petioles provide buoyancy, allow thecirculation of gases, and enable the leaves to float and performphotosynthesis. The species can grow in water up to 5 m deep but usuallyprefers shallow waters up to 2 m deep with muddy bottoms. The seedsstart germination when the water temperature is above 8 degrees C., withan estimated germination rate of 87%.

Various frequencies and amplitudes of ultrasound waves generated bysubmerged transducers were applied directly to water chestnuts.Ultrasound frequencies of 20-kHz, 100-kHz, 500-kHz, 1-MHz, and 2-MHzcaused substantial damage to plant cells and penetrated petiole tissues.20-kHz ultrasound caused the most significant cell damage after 10seconds of ultrasound exposure. The mortality rate of water chestnutplants treated with ultrasound aimed directly at water chestnut stemswas 97% with no seed production. The results of this laboratory studydemonstrated that ultrasound caused severe damage and plant death byaiming 20-kHz ultrasound waves directly on water chestnut stems.

Dense surface mats intercept up to 95% of incident sunlight and suppressnative submerged and floating plants as well as their associatedmicroscopic flora and fauna, successfully colonizing and ultimatelymonopolizing aquatic habitats. Water chestnut plants provide low valuefood for wildlife, as compared to the native species it replaces. Underdense water chestnut beds, dissolved oxygen was observed to be lower,which impacts fish and invertebrate communities. Water chestnutinfestation also restricts recreational water uses and navigation. Insome instances, water chestnut completely chokes a waterway and makesboating impossible.

Ultrasound is a sound wave, the frequency of which is above the audiblefrequency range for humans; i.e., frequency greater than 20,000 Hz. Therelevant physical principles of ultrasound include resonance phenomenaand acoustic intensity. Mechanisms of bioeffects of ultrasound include“thermal” and “mechanical” effects (National Council on RadiationProtection and Measurements 2002). When ultrasound waves are absorbed byplants, energy associated with ultrasound waves is converted into heat,or a thermal effect. An ultrasound wave, as it passes through a watermedium, can cause bubble activities known as acoustic cavitation, as amechanical effect.

Cavitation causes a wide variety of changes in plant cells, ranging frommicrostreaming of a cell's internal structure, to a mass disruption ofcell. Acoustic cavitation, the dominant mechanism in ultrasoundapplication, is especially evident on aquatic plants due to the presenceof gas in the interconnected chambers inside plant petioles. In general,the smaller the radius of the gas size, the greater the acousticcavitation.

Documented effects of ultrasound on plant cells include chromosomalanomalies, cell death, damage to or destruction of cellular structures,reduced growth rates and mitotic indices, changes in osmotic potentialof cells, and chemical changes within the liquid being cavitated.

The objective of this study was to determine the feasibility ofultrasonic control for water chestnut. A preliminary study was firstconducted to determine the optimal ultrasound wave to successfullyeradicate water chestnut plants. Ultrasound waves of various frequenciesand amplitudes generated by submerged transducers were applied directlyto water chestnut plants to determine the optimal ultrasound waves forwater chestnut management. A subsequent study was conducted to assessthe effectiveness of ultrasonic control of water chestnuts usingselected ultrasound waves under a controlled greenhouse environment.

Materials and Methods: Plant Materials

Harvested water chestnut plants were washed completely clean ofsediment, plankton and invertebrates and then placed in a 2800-litertank (1 m wide, 1.21 m deep, and 2.4 m long) constructed with stainlesssteel frames and polyvinyl chloride liners. The tank was filled withHoagland's solution containing 20 mg/L nitrogen as ammonium nitrate(NH₄NO₃), 5 mg/L phosphorus as monobasic sodium phosphate (naH₂PO₄.H₂O),20 mg/L potassium as potassium sulfate (K₂SO₄), 20 mg/L calcium ascalcium chloride (CaCl₂.2H₂O), 20 mg/L magnesium as magnesium sulfate(MgSO₄.7H₂O), and traces of manganese, boron, zinc, copper, and iron.The plants were kept in Hoagland's solution for at least two weeksbefore they were used in the experiments. Temperature in the greenhouseranged between 25 and 30 degrees C. during the study period. Dead leaveswere removed by hand, simulating the natural removal of dead leaves bywaves under field conditions.

Ultrasound Selection Study

A laboratory study was first performed to determine the optimalfrequency, acoustic pressure amplitude, and minimum ultrasound exposureduration required to successfully damage water chestnuts. Acomputer-controlled measurement system (NTR Systems, Seattle,Washington, USA), including three linear position manipulators and adigital oscilloscope as a digitizer (Model 9310, LeCroy Inc., Chestnut,N.Y., USA), was used to measure a two-dimensional cross-axis soundfield. A calibrated pvdf membrane hydrophone with a 0.2 mm diameterelectrode (Sonic Consulting, Inc. Wyndmoor, Pa., USA) was used as asound-wave sensor for all mega hertz frequencies. A calibrated 6 mmdiameter pvdf hydrophone (Model 8103, Brüel & Kjær, Nærum, Denmark) anda charge amplifier (Model 2635, Brüel & Kjær, Nærum, Denmark) were usedfor 20-kHz and submega hertz sound fields. The three dimensionalposition of a hydrophone was controlled by a computer via 3 linearmanipulators (NTR Systems, Seattle, Wash., USA).

A transducer was electronically connected to HP 3314A function generator(Hewlett Packard, CA) and an ENI A-300 RF power amplifier (ENI,Rochester, N.Y., USA). A 20-kHz sound field was generated by a 20-kHzhorn driven by a power source/supply from a sonicator (Model 450,Branson Inc., Danbury, Conn., USA). When a non-focusing transducer wasused, a hydrophone was scanned at a plane that was perpendicular to theacoustic axis of the sound field with a distance of 1 cm from thesurface of the transducer. When a focusing transducer was used, ahydrophone sensing element was scanned at the focal plane of the soundfield. The in situ spatial-peak pulse-average intensity, I_(SPPA)(National Council on Radiation Protection and Measurements 1983), wasalso calculated post-measurements.

After the sound field mapping, a portable single ultrasound transducerof known resonance frequency was then submerged in a 30-gallon tank. Awater chestnut leaf and petiole freshly dissected from a healthy plantwere mounted on a plastic holder. When a non-focusing transducer wasused, the sample/sample holder was positioned at 1 cm from thetransducer. Consequently, the petiole was exposed to a nearfieldultrasound field generated by the transducer. When a focusing transducerwas used, the plant leaf was placed within the ultrasound's focalregion. After the ultrasound exposure, the treated petiole was dissectedhorizontally. Each dissected cross section (approximately 1 mm thick) ofthe petiole was then examined under a microscope to examine the impactsof ultrasonic treatment on the water chestnut plant tissue.

Effectiveness of Ultrasound Study

The laboratory-scale effectiveness of ultrasound was conducted using 15tanks measuring 55 cm in diameter and 68 cm in height under a controlledgreenhouse environment. Temperature in the greenhouse ranged between 25and 30 degrees C. during the study period. Each tank was filled with 90liter of Hoagland's solution. Six water chestnut plants with an averagenumber of 18.3 leaves per plant were placed into each tank one weekbefore the beginning of the experiment (Table 2). Five tanks of plantswere treated with ultrasound aimed directly on petioles forapproximately 2 second per petiole; this was designated the petioletreatment.

Another five tanks of plants were treated with ultrasound aimed directlyat one target spot on each plant stem for 10 seconds; this wasdesignated the ‘stem” treatment. No ultrasound treatment was performedon the third group of five tanks; these five were the control group.Ultrasound transducers were submerged in water and aimed directly attarget plants from underneath. Plant mortality, number of leaves perplant and seed production were investigated daily as well as watertemperature and pH. Once a plant lost all its leaves and buoyancy, aplant was pronounced dead. Dead leaves were removed by hand, simulatingthe natural removal of dead leaves by waves under field conditions.Water temperature ranged between 22 and 26 degrees C. and water pHbetween 6.8 and 7.7 during the study period. Statistical analysis wasperformed using SPSS 14.0, and analysis of covariance (ANCOVA) was usedto control for the potentially confounding effect of the days inanalysis. Follow-up test of significant ANCOVA effects were comparedusing the Tukey's “honestly significant difference” (HSD) post hoc test.

Ultrasound Selection Study

The effects of ultrasound on plants include thermal effect and acousticcavitation. Since the acoustic attenuation of plants was relatively lowin the frequency-range tested, 20-kHz, 200-kHz, 500-kHz, 1-MHz, and2-MHz, as well as the short duration (less than 10 seconds), the thermaleffect is considered to be minimal (Fukuhara 2002). Acoustic cavitation(bubble activities under ultrasound) presumably played a primary role indamaging treated plants.

Among all the above tested frequencies, 20-kHz ultrasound of 1.8 MPaacoustic pressure amplitude demonstrated the most severe damage totreated water chestnut. Ruptures of water chestnut petioles was observedimmediately after 10 seconds of ultrasound treatment. Treated plantslost all leaves, buoyancy and viability within 24 hours. Under amicroscope, cell membrane disruption was observed on treated plants.Similar damage was caused by the other sub-megahertz and megahertzfrequencies (200-kHz, 500-kHz, 1-MHz, and 2-MHz), but longer exposureduration, up to two minutes, was needed to produce similar damages onwater chestnut plants.

A mechanical index (MI) developed as an indicator for the potential ofnon-thermal damage caused by acoustic cavitation was further used toverify the results. The MI index is defined as

${{MI} = \frac{P_{r}({MPa})}{\sqrt{f\mspace{14mu} ({MHz})}}},$

where P_(r) is the in situ peak negative acoustic pressure amplitudeexpressed in MPa and f is the central frequency in MHz (National Councilon Radiation Protection and Measurements 2002).

The results showed that the low frequencies used in this study were muchbelow the 1-MHz limit of diagnostic imaging applications. Nevertheless,F (P_(r), f), that is related to MI, may still be a good indicator forthe plant destruction due to acoustic cavitation. This is consistentwith our observation; the 20-kHz sound source caused the most severedamage to the plant.

Although the 500-kHz-focused sound field has the highest acousticpressure amplitude at its focal region, its F (P_(r), f), is still lowerthan that of 20-kHz, as its frequency is much higher (Table 1). The MIindex suggested that 20-kHz ultrasound of 1.8 MPa acoustic pressureamplitude has the highest MI value and can cause the severest damage toplants among the tested ultrasound waves.

Another disadvantage of the 500-kHz-focused sound field is that it iscritical to place the plant at its focus to get maximum acousticpressure amplitude. Since the 500-kHz focal zone is relatively small, itis time-consuming and impractical to use a focused sound field in alarge-scale management practice. A 20-kHz, non-focused sound field mayprovide a more effective management strategy.

Effectiveness of Ultrasound Study

After successfully selecting the optimal ultrasound wave, a study wasconducted to determine the optimal aiming location on water chestnuts,the petiole and the stem, and to assess the effectiveness of ultrasoundto control water chestnuts.

Aiming ultrasound directly on the central stem of water chestnut plantscaused immediate significant damages. The stems ruptured and the leavesgradually detached from the stems. No new leaf production was observedduring the 14-day post treatment observation period. Once a waterchestnut plant lost all its leaves and buoyancy, a plant was pronounceddead. Fourteen days after ultrasound treatment, the mortality rate ofstem treatment reached 97%. Only one out of 30 treated plants was stillalive, with only two leaves attached to its central stem (Table 2). Thistreated plant was observed for two months. Although it did not lose itsviability or all the leaves, it was never able to successfully produceseeds, which is the only means of reproduction by this annual plantspecies. Thus, the results suggest that ultrasound can cause highmortality of water chestnuts by aiming directly on plant stems for 10seconds under a controlled greenhouse environment.

In the petiole treatment, the treated areas were damaged immediately andturned brown. Leaves broke off from the treated spots or detached fromthe central stems. Twenty-six of the thirty treated plants lost alltheir leaves and were not able to produce new leaves by day 14. Thoseplants were considered dead; the mortality rate of the petiole treatmentwas observed to be 86.7% at day 14. The remaining four plants lost themajority of leaves with only a total of 11 leaves left among fourplants. Ten of the 11 remaining leaves were new growth from the centralstems (Table 2). Although the petiole treatment successfully damagedwater chestnut petioles, interrupted gas, nutrient and water transport,and resulted in loss of plant leaves, four of the 30 treated plants wereable to produce new leaves from the upper portion of the central stems(no seeds were produced during the two-month post treatmentobservation). Repeated treatments may be necessary or desirable. Itshould be noted; ultrasound treatment can be used to effectively stuntthe growth and effectively reduced the thickness of the plants, therebyreducing the size and density of plant coverage. Thus, ultrasoundtreatment may likewise be used to reduce the plant coverage in an areain order to allow recreation, allow boats to travel through, or toreduce surface coverage by plants or living matter in an area, therebyallowing sunlight and oxygen to permeate to lower levels in a body ofwater.

On average, each water chestnut included in this study developedapproximately 18 leaves. A total of 36 seconds of ultrasound exposurewas required to treat one plant. However, several seconds were requiredto reposition the ultrasound transducer to aim directly on each plantpetiole. Therefore, approximately two minutes were needed to applyultrasound to a single plant, which is longer than the 10-s exposureduration of the stem treatment. Compared to the petiole treatment, stemtreatment demonstrated greater potential and treatment efficiencybecause 1) the stem may be easier to locate by submersed transducer, 2)less repositioning of the transducer may be needed, and 3) less time isneeded to effectively treat the plant.

Water chestnuts in the control (no treatment) group grew during the14-day observation period. The number of leaves in the control groupincreased from 18.4 leaves/plant to 22.4 leaves/plant (Table 2), and oneadditional plant was observed in the control group via vegetativegrowth. An analysis of co-variance (ANCOVA) was performed to detectsignificant differences on numbers of leaves of water chestnuts afterstem treatment, petiole treatment and control (no treatment) during thestudy period. The numbers of leaves of water chestnuts significantlydifferent, F(2,38)=63.231, p=0.000 (Table 3).

Tukey's HSD test indicated that the numbers of leaves of water chestnutsin both stem and petiole treatments are significantly different from thenumber of leaves of water chestnuts in control (no treatment) (Table 4).A significantly less number of leaves found on both stem treatment(0.07±0.067) and petiole treatment (0.37±0.195) than control (notreatment) (22.4±0.403) at the end of the observation period (Table 2).Although the average number of leaves of the stem treatment wassignificantly less than that of the petiole treatment, water chestnutsin both stem and petiole treatments were significantly damaged byultrasound. The control group produced a total of 133 seeds by the endof the two-month post treatment observation period.

TABLE 1 Summary of Characteristics of Sound Sources Frequency −6 dB BeamHighest Acoustic (Hz) Diameter Pressure Amplitude I_(SPPA) F(P_(r), f) 20k 12 mm 1.9 MPa 860 W/cm² 13.4 200k 12 mm 1.2 MPa 340 W/cm² 2.7 500k 3 mm 2.8 MPa   1.9 kW/cm² 4.0   1M 12 mm 1.3 MPa 400 W/cm² 1.3   2M 12mm 1.3 MPa 400 W/cm² 0.9

TABLE 2 Measurements for average number of leaves per water chestnutplant (n = 30) of petiole treatment, stem treatment and control (notreatment). Initial Final Mean ± S.E. Mean ± S.E. Petiole Treatment18.60 ± 0.26 0.37 ± 0.20 Stem Treatment 18.00 ± 0.27 0.07 ± 0.07 Control(No Treatment) 18.40 ± 0.28 22.40 ± 0.40 

TABLE 3 Analysis of variance table for effects of ultrasound on waterchestnuts. Sum of Degrees of Squares Mean Square Source freedom (df)(SS) (MS) F-ratio p-value Time 1 512.171 512.171 29.304 0.000 Treatment2 2210.252 1105.126 63.231 0.000 Residual 38 664.153 17.478 Total 428417.373

TABLE 4 Mean differences between all possible pairs of treatments in thefeasibility study of ultrasonic treatment of water chestnuts. ControlPetiole Stem (No Treatment) Treatment Treatment Control (No Treatment)0.000 Petiole Treatment 13.083(0.000) 0.000 Stem Treatment 16.955(0.000)3.871(0.000) 0.000

Also assessed were the impacts of ultrasound on fish populations in90-gallon tanks, each containing six water chestnut plants and 12minnows—Northern redbelly dace (Phoxinus eos) and fathead minnow(Pimephales promelas)—averaging 2.3 inches (5.9 cm) in length that werecollected locally in Essex County, New York. Ultrasound waves of 20 kHzwere emitted into treatment tanks for six continuous hours. Observedwere fish mortalities and behaviors every hour during the treatment aswell as at 24, 48 and 72 hours after the six-hour ultrasonic treatment.No fish died as a result of either treatment (n=4) or control (n=4)tanks, nor were any abnormal fish behavior observed. The results of thisstudy suggested that the ultrasound emissions can be controlled suchthat one specie is treated and/or eliminated with other species mayremain intact and otherwise unaffected. For example, water chestnutplants may be successfully eradicated by aiming 20 kHz ultrasound wavesdirectly on the plants, while the same ultrasound parameters leave fishpopulations unaffected and unharmed.

Static Ballast Water Test

A single transducer static test (i.e., water was not flowing) wasperformed on a tubular module having one probe inserted through its wallinto its interior. The ultrasound field measurement was performed in awater tank filled with distilled water and the walls of the tank weremounted with sound absorbing material to minimize the reflection of thewalls. The ultrasound field measurement of a single probe was conductedusing a hydrophone of diameter 0.6 mm. It was achieved by scanning thehydrophone in the neighboring area as shown in FIG. 19. FIG. 19demonstrates the normalized ultrasound amplitude distribution. Theresults demonstrated 100% mortality on the following with contact timeof 10 sec.

Organisms time (s) mortality Aquatic insects Acilius sp. 10 100% Aquaticinsects Dytiscidae 10 100% Aquatic insects Stratiomys sp. 10 100%Aquatic insects Tipulidae 10 100% Aquatic insects Simulidae 10 100%Aquatic insects leeches 10 100% Aquatic insects Belostoma flumineum 10100% Aquatic insects Mesovelia sp. 10 100% Aquatic insectsOdonata/Anisoptera 10 100% Aquatic insects Odonata/Zygoptera 10 100%Aquatic insects isopoda 10 100% Aquatic insects amphiopoda 10 100%Zooplankton Holopedidae 10 100% Zooplankton Daphnia 10 100% Zooplanktonspiny water flea 10 100% bivalve snail 10 100% bivalve Asian Clam-Smallin 10 100% size

As can be seen, the static water test, using a single transducer,provided 100% mortality of a number of organisms after 10 seconds.

What is claimed is:
 1. An apparatus for treatment of ballast water, comprising: (a) a generally cylindrical module having a tubular wall and an open interior along its axis; (b) a plurality of transducer probes disposed in the wall of said module, each of said probes having a first end and a second end, said second end being located within said open interior of said module; (c) a power supply for at least one of said transducer probes; wherein said transducer probes are capable of emitting ultrasonic waves at said second end.
 2. The apparatus of claim 1, wherein said plurality of transducer probes are arranged in a substantially helical formation extending along the length of the module.
 3. The apparatus of claim 1, wherein each of said transducer probes is connected to at least one power supply.
 4. The apparatus of claim 1 comprising about 5 to about 20 transducer probes.
 5. The apparatus of claim 1, wherein each of said transducer probes is about 300 to about 500 mm as measured from first end to second end.
 6. The apparatus of claim 1, wherein each of said transducer probes is separated from an adjacent transducer probe by about 100 mm as measured from the center of the axis of the transducer probe at said second end of each transducer probe.
 7. The apparatus of claim 1, wherein each of said transducer probes emits ultrasonic waves at a frequency of about 20 kHz to about 3 MHz.
 8. The apparatus of claim 1, further comprising a water pump for pumping said ballast water through said open interior of said module.
 9. A method for treatment of ballast water, comprising the steps of: (a) providing an untreated ballast water source including at least one organism to be destroyed; (b) providing an apparatus comprising: (i) a generally cylindrical module having a tubular wall and an open interior along its axis; (ii) a plurality of transducer probes disposed in the wall of said module, each of said probes having a first end and a second end, said second end being located within said open interior of said module; and (iii) a power supply for at least one of said transducer probes; wherein said transducer probes are capable of emitting ultrasonic waves at said second end; (c) powering on at least one of said transducer probes, thereby emitting ultrasonic waves within said interior; and (d) flowing said ballast water through said interior, whereby said ballast water is in contact with said ultrasonic waves.
 10. The method of claim 9, wherein said plurality of transducer probes are arranged in a substantially helical formation extending along the length of the module.
 11. The method of claim 9, wherein each of said transducer probes is connected to at least one power supply.
 12. The method of claim 9 comprising about 5 to about 20 transducer probes.
 13. The method of claim 9, wherein each of said transducer probes is about 300 to about 500 mm as measured from first end to second end.
 14. The method of claim 9, wherein each of said transducer probes is separated from an adjacent transducer probe by about 100 mm as measured from the center of the axis of the transducer probe at said second end of each transducer probe.
 15. The method of claim 9, wherein each of said transducer probes emits ultrasonic waves at a frequency of about 20 kHz to about 3 MHz.
 16. The method of claim 9, further comprising a water pump for pumping said ballast water through said open interior of said module.
 17. The method of claim 9, comprising more than one of said modules connected to each other in series wherein each of said modules has an open interior and each of said open interiors are in communication with each other.
 18. The method of claim 17, wherein said step of flowing said ballast water comprises the step of flowing said ballast water through the open interior of each of said modules.
 19. The method of claim 18, wherein the connection between each of said modules is substantially water-tight.
 20. The method of claim 17, wherein each of said modules includes a plurality of transducer probes arranged in a substantially helical orientation along the length of each of said modules. 